Belcher's gull (''Larus belcheri''), also known as the band-tailed gull, is a bird in the family

Laridae Laridae is a family of seabirds in the order Charadriiformes that includes the gulls, terns (including white terns), noddies, and skimmers. It includes around 100 species arranged into 22 genera. They are an adaptable group of mostly aerial bird ...

found along the

Pacific The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean, or, depending on the definition, to Antarctica in the south, and is bounded by the cont ...

coast of

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a considerably smaller portion in the Northern Hemisphere. It can also be described as the southern Subregion#Americas, subregion o ...

. It formerly included the very similar

Olrog's gull Olrog's gull (''Larus atlanticus'') is a species of gull found along the Atlantic coast of southern Brazil, Uruguay, and northern Argentina. It was formerly considered a subspecies of the very similar ''Belcher's gull, L. belcheri''. It is a larg ...

as a

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

, but that bird occurs on the Atlantic coast of South America and is now accepted as ''Larus atlanticus''. Belcher's gull is a medium-sized gull with a blackish mantle, white head and underparts, a black band on the otherwise white tail, and a yellow bill with a red and black tip. Non-breeding adults have a brownish-black head and a white eye-ring. The name of this bird commemorates the British explorer Sir

Edward Belcher Sir Edward Belcher (27 February 1799 – 18 March 1877) was a British naval officer, hydrographer, and explorer. Born in Nova Scotia, he was the great-grandson of Jonathan Belcher, who served as a colonial governor of Massachusetts, New ...

, who performed survey work on the Pacific coast of South America.

Description

Belcher's gull grows to a length of about . The sexes are similar in appearance, and in the breeding season, the adult has a white head and very pale grey neck and underparts. The mantle and back are greyish-black, and the tail is white with a broad black subterminal band and a white trailing edge. The wing coverts and primaries are black and the secondaries dark grey with white tips. The eye is black, the bill yellow with a distinctive red and black tip, and the legs and feet yellow. Outside the breeding season the head is dark brown with a white ring surrounding the eye. The juvenile is mottled brown and white and attains the adult plumage during its third year. Belcher's gull can be confused with the slightly larger

kelp gull The kelp gull (''Larus dominicanus''), also known as the Dominican gull, is a gull that breeds on coasts and islands through much of the Southern Hemisphere. The nominate ''L. d. dominicanus'' is the subspecies found around South America, pa ...

(''Larus dominicanus''), but that species has a small white tip on its otherwise black wing and lacks the black tail band found on Belcher's gull.

Distribution and habitat

Belcher's gull is found on the Pacific coast of South America. Its range extends from northern Peru to northern Chile in the area influenced by the

Humboldt Current The Humboldt Current, also called the Peru Current, is a cold, low-salinity ocean current that flows north along the western coast of South America.Montecino, Vivian, and Carina B. Lange. "The Humboldt Current System: Ecosystem components and pro ...

. Its habitat includes rocky shores, bays and offshore islands. It ventures several kilometres offshore to forage and also feeds on rocky shores when the tide is out. It is a non-migratory species.

Ecology

Belcher's gull is an

omnivore An omnivore () is an animal that regularly consumes significant quantities of both plant and animal matter. Obtaining energy and nutrients from plant and animal matter, omnivores digest carbohydrates, protein, fat, and fiber, and metabolize t ...

and

scavenger Scavengers are animals that consume Corpse decomposition, dead organisms that have died from causes other than predation or have been killed by other predators. While scavenging generally refers to carnivores feeding on carrion, it is also a he ...

. It feeds on fish, crabs, molluscs and carrion, and seasonally on the eggs and nestlings of seabirds. It often associates with Guanay cormorants, pestering them until they regurgitate their prey, which it then consumes. Breeding takes place from December onwards in small colonies of up to one hundred pairs. The nest is a scrape in the sand or among rocks near the high tide line. There are usually three eggs averaging , pale blotched with dark olive markings.

Status

Belcher's gull is estimated to have a total population of under ten thousand individuals and an estimated distribution range of . Persecution of this bird by humans has diminished, and its population is thought to be increasing. For these reasons, despite its small total population size and limited range, the

International Union for Conservation of Nature The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the stat ...

considers it to be of "

least concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wil ...

References

{{Taxonbar, from=Q478233

Belcher's gull Belcher's gull (''Larus belcheri''), also known as the band-tailed gull, is a bird in the family Laridae found along the Pacific coast of South America. It formerly included the very similar Olrog's gull as a subspecies, but that bird occurs on t ...

Birds of Chile Birds of Ecuador Birds of Peru Western South American coastal birds